On Tue, Apr 5, 2011 at 3:59 PM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> On Mon, Apr 04, 2011 at 02:49:54PM -0400, Nathan Froyd wrote:>> This patch does just what $SUBJECT suggests.>> v2, now with obstacks!
Still one TODO in doc/rtl.texi:
@findex LOG_LINKS
@item LOG_LINKS (@var{i})
A list (chain of @code{insn_list} expressions) giving information about
dependencies between instructions within a basic block. Neither a jump
nor a label may come between the related insns. These are only used by
the schedulers and by combine. This is a deprecated data structure.
Def-use and use-def chains are now preferred.
Ciao!
Steven

On Tue, Apr 05, 2011 at 04:42:27PM +0200, Steven Bosscher wrote:
> On Tue, Apr 5, 2011 at 3:59 PM, Nathan Froyd <froydnj@codesourcery.com> wrote:> > v2, now with obstacks!> > @findex LOG_LINKS> @item LOG_LINKS (@var{i})> A list (chain of @code{insn_list} expressions) giving information about> dependencies between instructions within a basic block. Neither a jump> nor a label may come between the related insns. These are only used by> the schedulers and by combine. This is a deprecated data structure.> Def-use and use-def chains are now preferred.
So, being somewhat RTL-ignorant, is this patch going in the wrong
direction? Should combine be using DF instead of constructing
LOG_LINKS?
-Nathan

On Tue, Apr 5, 2011 at 4:51 PM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> On Tue, Apr 05, 2011 at 04:42:27PM +0200, Steven Bosscher wrote:>> On Tue, Apr 5, 2011 at 3:59 PM, Nathan Froyd <froydnj@codesourcery.com> wrote:>> > v2, now with obstacks!>>>> @findex LOG_LINKS>> @item LOG_LINKS (@var{i})>> A list (chain of @code{insn_list} expressions) giving information about>> dependencies between instructions within a basic block. Neither a jump>> nor a label may come between the related insns. These are only used by>> the schedulers and by combine. This is a deprecated data structure.>> Def-use and use-def chains are now preferred.>> So, being somewhat RTL-ignorant, is this patch going in the wrong> direction?
Oh, not at all. Just documentation that needs updating! :)
Ciao!
Steven

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On 04/05/11 08:51, Nathan Froyd wrote:
> On Tue, Apr 05, 2011 at 04:42:27PM +0200, Steven Bosscher wrote:>> On Tue, Apr 5, 2011 at 3:59 PM, Nathan Froyd <froydnj@codesourcery.com> wrote:>>> v2, now with obstacks!>>>> @findex LOG_LINKS>> @item LOG_LINKS (@var{i})>> A list (chain of @code{insn_list} expressions) giving information about>> dependencies between instructions within a basic block. Neither a jump>> nor a label may come between the related insns. These are only used by>> the schedulers and by combine. This is a deprecated data structure.>> Def-use and use-def chains are now preferred.> > So, being somewhat RTL-ignorant, is this patch going in the wrong> direction? Should combine be using DF instead of constructing> LOG_LINKS?
Ideally, we'd like to get rid of LOG_LINKS in favor of DF; however, I
don't think anyone has looked at what would be needed to make that
happen for combine.c or at what the memory & compile-time implications
might be for such a change.
I still think your patch is a step forward as it should reduce the load
on the garbage collector.
Jeff
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